CN113574431B

CN113574431B - Optical fiber bundle structure, optical connector, optical fiber connection structure, and method for manufacturing optical fiber bundle structure

Info

Publication number: CN113574431B
Application number: CN202080020929.4A
Authority: CN
Inventors: 川崎浩平; 杉崎隆一; 塚本昌义; 高桥正典; 高坂繁弘; 前田幸一
Original assignee: Furukawa Electric Co Ltd
Current assignee: Furukawa Electric Co Ltd
Priority date: 2019-03-27
Filing date: 2020-03-25
Publication date: 2023-08-25
Anticipated expiration: 2040-03-25
Also published as: JP7479349B2; CN113574431A; JPWO2020196627A1; WO2020196627A1; US11940649B2; US20240142697A1; US20240151898A1; US20220003924A1

Abstract

The invention aims to provide an optical fiber bundle structure with small loss. The optical fiber bundle structure is provided with: a plurality of optical fiber cores; a cross elimination member through which a plurality of optical fiber cores are passed in a longitudinal direction; and a grip member which imparts gripping force to the cross-cancellation member, wherein the plurality of optical fiber cores sequentially have a thin diameter portion, a tapered portion, a thick diameter portion, and a resin coating portion from the front end, and wherein the cross-cancellation member is formed with a slit having a width in a cross section orthogonal to the longitudinal direction of the cross-cancellation member, centered at a point extending from the front end to the middle of the rear end side of the cross-cancellation member, the point being obtained by dividing each side of a polygon circumscribed by the plurality of optical fiber cores by the number of optical fiber cores in contact with the side, and wherein the width of the slit located at each side is equal to or more than a difference between the length of one side of the polygon circumscribed by the plurality of optical fiber cores at the terminal end portion of the slit located at the rear end side and the length of one side of the polygon circumscribed by the plurality of optical fiber cores at the front end side.

Description

Optical fiber bundle structure, optical connector, optical fiber connection structure, and method for manufacturing optical fiber bundle structure

Technical Field

The present invention relates to an optical fiber bundle structure, an optical connector, an optical fiber connection structure, and a method for manufacturing the optical fiber bundle structure.

Background

An optical fiber having a plurality of core portions, i.e., a multicore optical fiber, is known. In order to connect a multicore fiber and a single core fiber, an optical fiber bundle structure has been proposed in which cores of the single core fiber are arranged at positions corresponding to the cores of the multicore fiber (for example, see patent literature 1).

Patent document 1 discloses an optical fiber bundle structure including: a plurality of optical fiber cores which sequentially have a small diameter portion, a tapered portion which is tapered toward the rear end and has a larger diameter, a large diameter portion, and a resin coating portion which is coated with a resin; and a capillary tube that accommodates the optical fiber cores. In this optical fiber bundle structure, the small diameter portion and the resin coating portion of the optical fiber core wire are abutted against the inner surface of the capillary tube, whereby the optical fiber core wire is positioned.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2017-181791

Disclosure of Invention

Problems to be solved by the invention

However, in the optical fiber bundle structure of patent document 1, the optical fiber core is not positioned at the tapered portion and the thick diameter portion of the optical fiber core. As a result, in this optical fiber bundle structure, although the optical fiber core is positioned at the small diameter portion and the resin coating portion of the optical fiber core, the optical fiber core may intersect at the taper portion and the large diameter portion. Bending loss occurs when the optical fiber cores cross, and is thus not preferable.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical fiber bundle structure with small loss, an optical connector, an optical fiber connection structure, and a method for manufacturing the optical fiber bundle structure.

Means for solving the problems

In order to solve the above-described problems and achieve the object, an optical fiber bundle structure according to an aspect of the present invention includes: a plurality of optical fiber cores; a cross elimination member through which the plurality of optical fiber cores extend in a longitudinal direction; and a grip member that imparts gripping force to the cross canceling member, wherein the plurality of optical fiber cores sequentially have a glass fiber portion and a resin coating portion that coats the glass fiber, the glass fiber portion sequentially having a small diameter portion, a tapered portion, and a large diameter portion from a front end, and wherein the cross canceling member is formed with a slit having a width in a cross section orthogonal to the longitudinal direction of the cross canceling member, the slit being centered at a point in a middle of the cross canceling member extending from the front end to a rear end side of the cross canceling member, the point being obtained by dividing each side of a polygon that circumscribes the plurality of optical fiber cores by a number of optical fiber cores that meet the side, the width of the slit at each side being a difference between a length of a side of the polygon that circumscribes the plurality of optical fiber cores at a terminal portion of the slit at a rear end side and a length of a side of the polygon that circumscribes the plurality of optical fiber cores at a front end side.

An optical fiber bundle structure according to an aspect of the present invention is characterized by comprising: a plurality of optical fiber cores; a cross elimination member through which the plurality of optical fiber cores extend in a longitudinal direction; and a grip member that imparts gripping force to the cross canceling member, wherein the plurality of optical fiber cores sequentially have a glass fiber portion and a resin coating portion that coats the glass fiber, the glass fiber portion sequentially having a thin diameter portion, a tapered portion, and a thick diameter portion from a front end, and wherein the cross canceling member is formed with a slit having a width in a cross section orthogonal to the longitudinal direction of the cross canceling member about a point in a middle of the cross canceling member extending from the front end to a rear end side, the point being obtained by equally dividing each side of a substantially polygon circumscribing the plurality of optical fiber cores by the number of optical fiber cores in contact with the side, each vertex portion of the substantially polygon circumscribing the plurality of optical fiber cores having a curved shape, and a total of the widths of the slit located at each side is a length of an outer circumference of the plurality of optical fibers surrounded in a shortest manner and a length of the outer circumference surrounded by the plurality of optical fiber cores in a shortest manner at a terminal portion of the slit located at a rear end side.

In addition to the above-described invention, in an aspect of the present invention, the gripping member is a ring fitted to a distal end side of the crossover-eliminating member.

In addition to the above-described invention, in an optical fiber bundle structure according to an aspect of the present invention, the plurality of optical fiber cores are arranged in a square shape at the small diameter portion.

In addition, in the optical fiber bundle structure according to one aspect of the present invention, the plurality of optical fiber cores is four or nine.

In addition to the above-described invention, in an optical fiber bundle structure according to an aspect of the present invention, the plurality of optical fiber cores are arranged most closely in a hexagonal shape at the small diameter portion.

In addition, in the optical fiber bundle structure according to one aspect of the present invention, the plurality of optical fiber cores is seven or nineteen.

In addition, in an optical connector according to an aspect of the present invention, the optical connector includes the optical fiber bundle structure, and the grip member is a ferrule formed with a hole portion that imparts a grip force to the inserted crossover-elimination member.

In addition, an optical fiber connection structure according to an aspect of the present invention is characterized by comprising: the optical fiber bundle structure described above; and a multi-core optical fiber having a plurality of core portions connected to the cores of the plurality of optical fiber cores, and a cladding portion formed on the outer periphery of the core portions.

In addition, an optical fiber connection structure according to an aspect of the present invention is characterized by comprising: the optical fiber bundle structure described above; and a plurality of light receiving/emitting units connected to cores of the plurality of optical fiber cores.

In addition, a method for manufacturing an optical fiber bundle structure according to an aspect of the present invention is characterized by comprising: an insertion step of inserting a crossover-eliminating member into a circular ring-shaped guide member so that a protrusion protruding in an inner circumferential direction of the guide member is fitted into a slit, the crossover-eliminating member being configured to allow a plurality of optical fiber cores to pass through in a longitudinal direction, the plurality of optical fiber cores having a glass fiber portion and a resin coating portion coating a resin on the glass fiber in this order from a front end, the slit having a width in a cross section orthogonal to the longitudinal direction of the crossover-eliminating member centered on a point extending from a front end to a rear end side of the crossover-eliminating member, the point being obtained by dividing each side of a polygon circumscribed by the plurality of optical fiber cores by a number of optical fiber cores in contact with the side, the width of the slit on each side being equal to or greater than a difference between a length of one side of a polygon circumscribed by the plurality of optical fiber cores at a terminal end of the slit on a rear end side and a length of one side of the polygon circumscribed by the plurality of optical fiber cores on a front end side; a penetration step of penetrating the plurality of optical fiber cores from the front end side to the rear end side of the cross canceling member while the plurality of optical fiber cores are aligned in a predetermined arrangement; a pulling step of pulling the optical fiber core wire toward a rear end side while applying a gripping force to the cross canceling member until a small diameter portion of the glass fiber portion is positioned inside the cross canceling member, the glass fiber portion having the small diameter portion, the tapered portion, and the large diameter portion in this order from a front end; a detaching step of detaching the guide member from the crossover-eliminating member; and a ferrule insertion step of inserting the crossover-eliminating member into the hole of the ferrule while applying a gripping force to the crossover-eliminating member.

In addition to the above-described invention, a method for manufacturing an optical fiber bundle structure according to an aspect of the present invention is characterized in that the drawing step includes: a first pulling step of pulling the optical fiber core wire toward a rear end side until a rear end of the tapered portion of the glass fiber portion is positioned inside the crossover-eliminating member; and a second pulling step of pulling the optical fiber core wire toward a rear end side until the small diameter portion of the glass fiber portion is positioned inside the cross canceling member, the detaching step being performed between the first pulling step and the second pulling step.

In the method for manufacturing an optical fiber bundle structure according to one aspect of the present invention, the protruding portion of the guide member has a thickness equal to or greater than a difference between a length of one side of a polygon that is circumscribed by the plurality of optical fiber cores at a rear end of the tapered portion of the optical fiber core and a length of one side of a polygon that is circumscribed by the plurality of optical fiber cores at a front end of the tapered portion of the optical fiber core.

Effects of the invention

According to the present invention, there are achieved the effects of realizing a fiber bundle structure, an optical connector, a fiber connection structure, and a method for manufacturing the fiber bundle structure, which have small loss.

Drawings

Fig. 1 is a schematic diagram showing the structure of a fiber bundle structure according to embodiment 1 of the present invention.

Fig. 2 is a cross-sectional view corresponding to line A-A of fig. 1.

Fig. 3 is a schematic view showing the structure of the optical fiber core wire shown in fig. 1.

Fig. 4 is a schematic view showing the structure of the cross canceling member shown in fig. 1.

Fig. 5 is a sectional view corresponding to the line E-E of fig. 4.

Fig. 6 is a cross-sectional view corresponding to the line F-F of fig. 4.

Fig. 7 is a sectional view corresponding to line B-B of fig. 1.

Fig. 8 is a sectional view corresponding to line C-C of fig. 1.

Fig. 9 is a sectional view corresponding to the line D-D of fig. 1.

Fig. 10 is a cross-sectional view showing an optical fiber core wire and a cross-over eliminating member according to modification 1.

Fig. 11 is a cross-sectional view showing an optical fiber core wire and a cross-canceling member according to modification 2.

Fig. 12 is a view showing a slit of the cross canceling member of modification 2.

Fig. 13 is a cross-sectional view showing an optical fiber core wire and a cross-over eliminating member according to modification 3.

Fig. 14 is a cross-sectional view of the optical fiber core wire and the cross-canceling member according to modification 4, corresponding to the line B-B in fig. 1.

Fig. 15 is a cross-sectional view of the optical fiber core wire and the cross-over eliminating member in modification 4, corresponding to the C-C line in fig. 1.

Fig. 16 is a schematic diagram showing the structure of an optical connector of embodiment 2.

Fig. 17 is a view showing a state in which the optical fiber core wire of fig. 16 is pushed into the distal end side.

Fig. 18 is a schematic diagram showing the structure of the optical fiber connection structure of embodiment 3.

Fig. 19 is a sectional view corresponding to the G-G line of fig. 18.

Fig. 20 is a schematic diagram showing the structure of the optical fiber connection structure of embodiment 4.

Fig. 21 is a sectional view corresponding to the line H-H of fig. 20.

Fig. 22 is a flow chart illustrating a method of manufacturing a fiber optic bundle structure.

Fig. 23 is a schematic view showing the structure of the guide member.

Fig. 24 is an I-view of fig. 23.

Fig. 25 is a view showing a state in which the cross canceling member is inserted into the guide member.

Fig. 26 is a view showing a state in which the optical fiber core wire is inserted into the cross canceling member.

Fig. 27 is a sectional view corresponding to the J-J line of fig. 26.

Fig. 28 is a view showing a state in which the rear end of the tapered portion of the optical fiber core is located inside the guide member.

Fig. 29 is a sectional view corresponding to the line K-K of fig. 28.

Fig. 30 is a view showing a state where the crossover-eliminating member is inserted into the small diameter portion of the optical fiber core wire.

Fig. 31 is a sectional view corresponding to the L-L line of fig. 30.

Detailed Description

Hereinafter, embodiments (hereinafter, embodiments) for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. In the description of the drawings, the same reference numerals are given to the same parts. The drawings are schematic, and the relationship between the dimensions of the elements, the ratio of the elements, and the like may be different from reality. Further, the drawings may include portions having different dimensional relationships and ratios.

(embodiment 1)

[ fiber bundle Structure ]

First, a fiber bundle structure will be described. Fig. 1 is a schematic diagram showing the structure of a fiber bundle structure according to embodiment 1 of the present invention. Fig. 2 is a cross-sectional view corresponding to line A-A of fig. 1. Hereinafter, along the paper surface of fig. 1, the left side is set as the front end and the right side is set as the rear end.

The optical fiber bundle structure 1 includes: a plurality of optical fiber cores 2 of the same diameter; a crossover eliminating member 3 through which the plurality of optical fiber cores 2 penetrate in the longitudinal direction; and a grip member 4 that imparts a grip force to the cross cancellation member 3.

The optical fiber core 2 includes a core 21, a cladding 22 formed on the outer periphery of the core 21, and a cladding 23 made of resin. The optical fiber cores 2 are held in a predetermined arrangement. In the example shown in fig. 2, the cores 21 of the four optical fiber cores 2 are arranged so as to be at the vertex positions of a square (regular polygon). That is, the cores 21 of the adjacent optical fiber cores 2 are arranged at substantially the same distance from each other. The square arrangement is a square arrangement when the centers of the cores 21 are connected in this manner.

The core 21 is made of quartz glass doped with germanium or the like and having a high refractive index, for example. The refractive indices of the plurality of cores 21 may be the same, but may also be different. The cladding 22 is made of a material having a lower refractive index than the core 21, for example, pure silica glass or the like to which no refractive index adjusting dopant is added.

Fig. 3 is a schematic view showing the structure of the optical fiber core wire shown in fig. 1. The optical fiber core wire 2 has, in order from the distal end, a glass fiber portion 2a and a resin coating portion 2b that coats glass fibers with a resin. The glass fiber portion 2a has a small diameter portion 2aa, a tapered portion 2ab, and a large diameter portion 2ac in this order from the tip.

The diameter of the clad (diameter of the clad 22) is 40 μm in the small diameter portion 2aa, but may be, for example, 30 μm to 80 μm in the clad diameter and 6 μm to 12 μm in the core diameter (diameter of the core 21). The core diameter is the same in the glass fiber portion 2a (the small diameter portion 2aa, the tapered portion 2ab, and the large diameter portion 2 ac) and the resin coating portion 2b.

The cladding diameter becomes smaller as the taper portion 2ab is toward the tip. The taper portion 2ab has a cladding diameter of 40 μm at the tip and 80 μm at the rear.

The small diameter portion 2aa and the tapered portion 2ab are formed by removing the coating portion 23 of the resin coating portion 2b, exposing the glass fiber inside, and chemically etching the exposed glass fiber to a predetermined length on the tip side. That is, the diameter of the small diameter portion 2aa and the tapered portion 2ab is smaller than the diameter of the large diameter portion 2ac. For the large diameter portion 2ac, for example, the cladding diameter is 80 μm.

For the resin coating portion 2b, for example, the cladding diameter is 80 μm, and the outer periphery thereof is covered with the coating portion 23. The resin coating portion 2b has a coating diameter (diameter of the coating portion 23) of 125 μm, for example.

Fig. 4 is a schematic view showing the structure of the cross canceling member shown in fig. 1. Fig. 5 is a sectional view corresponding to the line E-E of fig. 4. Fig. 6 is a cross-sectional view corresponding to the line F-F of fig. 4. Fig. 4 to 6 are diagrams showing a state in which no gripping force is applied to the cross canceling member 3 from the gripping member 4.

The crossover-eliminating member 3 has: a through hole 3a (see fig. 5) formed on the rear end side of the cross canceling member 3; a slit 3b (see fig. 4) extending from the front end of the cross canceling member 3 to the middle of the rear end side; and a cutout 3c (see fig. 6) formed in a region formed by projecting the through hole 3a to the distal end side of the cross canceling member 3.

As shown in fig. 2, the resin coating portions 2b of the four optical fiber cores 2 are inserted into the through holes 3a. The through hole 3a is a square having a length of one side substantially equal to the length of the two resin coating portions 2b, and has a length of 250 μm, for example.

The slit 3b has a width centered on a point at which each side of the polygon that circumscribes the plurality of optical fiber cores 2 is divided equally by the number of optical fiber cores 2 that are in contact with the side, in a cross section (cross section orthogonal to the longitudinal direction) corresponding to the E-E line shown in fig. 5. In the case where the number of optical fiber cores 2 is four as shown in fig. 2, the cross canceling member 3 has four slits 3b having a width w centered at the midpoints of the sides of the quadrangle circumscribing the optical fiber cores 2. The width w of the slit 3b is 170 μm, for example.

The slit 3c has, for example, a 40 μm side, and the slit 3b and the slit 3c have, as indicated by the chain line, a square having the same size as the through hole 3a, that is, a 250 μm side, in a state where the pinching force from the pinching member 4 is not applied to the cross cancel member 3.

As shown in fig. 1, the cross canceling member 3 is narrowed in width of the slit 3b toward the tip end side by the gripping force applied by the gripping member 4. The grip force is a force applied in the center direction of the cross-sectional plane orthogonal to the longitudinal direction of the cross-canceling member 3.

Fig. 7 is a sectional view corresponding to line B-B of fig. 1. In fig. 7, since the width w1 of the slit 3b is 170 μm without narrowing, the square formed by the slit 3b and the cutout 3c is a square having one side of 250 μm, which is approximately equal to the length of the two resin coating portions 2b.

Fig. 8 is a sectional view corresponding to line C-C of fig. 1. In fig. 8, the square formed by the slit 3b and the cutout 3c is a quadrangle having 160 μm on one side, which is substantially equal in length to the cladding diameter at the rear ends of the two taper portions 2 ab. That is, the width w2 of the slit 3b is 80. Mu.m.

Fig. 9 is a sectional view corresponding to the line D-D of fig. 1. In fig. 9, the width of the slit 3b becomes substantially zero. At this time, the quadrangle formed by the cutout portion 3c is a quadrangle having one side of 80 μm which is substantially equal to the cladding diameter at the tip ends of the two taper portions 2 ab.

The grip member 4 is a ring fitted to the distal end side of the cross cancellation member 3. However, the grip member 4 may be an elastic member that imparts elastic force from the outer periphery of the cross canceling member 3 and a hole into which the cross canceling member 3 is fitted, as long as it imparts gripping force to the cross canceling member 3.

Here, the width of the slit 3b located at each side is preferably equal to or greater than the difference between the length of one side of the polygon that is circumscribed by the plurality of optical fiber cores 2 at the terminal end portion of the slit 3b on the rear end side and the length of one side of the polygon that is circumscribed by the plurality of optical fiber cores 2 on the front end side. Specifically, in the case where the number of optical fiber cores 2 shown in fig. 2 is four, the difference between the length of one side of the quadrangle that is externally connected to the four optical fiber cores 2 (resin coating portion 2 b) at the terminal end portion of the slit 3b on the rear end side, that is, 250 μm, and the length of one side of the quadrangle that is externally connected to the four optical fiber cores 2 (small diameter portion 2 aa) at the front end side, that is, 80 μm is 170 μm, and the width of the slit 3b of the cross canceling member 3 is 170 μm. As a result, the width of the slit 3b is narrowed from the rear end side toward the front end side in accordance with the reduction in diameter of the optical fiber core wire 2, and the cross canceling member 3 abuts the optical fiber core wire 2 over the entire area in the longitudinal direction of the optical fiber core wire 2, thereby preventing the optical fiber core wire 2 from crossing.

Modification 1

Fig. 10 is a cross-sectional view showing an optical fiber core wire and a cross-over eliminating member according to modification 1. Fig. 10 is a cross-sectional view corresponding to line A-A of fig. 1. The optical fiber bundle structure of modification 1 includes nine optical fiber cores 2 and a cross canceling member 3A.

The optical fiber cores 2 are arranged in a square arrangement that is square when the centers of the cores 21 are connected. The cross cancellation member 3A has a quadrangular through hole 3Aa. In this way, the optical fiber cores 2 can be arranged in square shapes such as 2×2, 3×3, 4×4, and … … regardless of the number of the optical fibers. In this case, the shape of the through hole formed in the cross canceling member may be substantially square.

Modification 2

Fig. 11 is a cross-sectional view showing an optical fiber core wire and a cross-canceling member according to modification 2. Fig. 11 is a cross-sectional view corresponding to line A-A of fig. 1. The optical fiber bundle structure of modification 2 includes seven optical fiber cores 2 and a cross canceling member 3B. Further, one treatment at the center of seven may be treated as a dummy (japanese: dow chemical one), and the number of optical fiber cores 2 may be six.

The optical fiber cores 2 are arranged in a hexagonal closest arrangement, and the outer cores 21 are connected at their centers to form a hexagonal shape. The cross canceling member 3B has a hexagonal through hole 3Ba.

Fig. 12 is a view showing a slit of the cross canceling member of modification 2. Fig. 12 is a sectional view corresponding to the line E-E shown in fig. 5. The cross canceling member 3B has six slits 3Bb centered on the midpoints of the sides of the hexagon circumscribing the optical fiber core wire 2. In a state where no pinching force is applied to the cross canceling member 3B, the slit 3Bb and the cutout portion 3Bc are formed in a hexagonal shape having the same size as the through hole 3Ba as indicated by the dash-dot line.

Modification 3

Fig. 13 is a cross-sectional view showing an optical fiber core wire and a cross-over eliminating member according to modification 3. Fig. 13 is a cross-sectional view corresponding to line A-A of fig. 1. The optical fiber bundle structure of modification 3 includes nineteen optical fiber cores 2 and a crossover-eliminating member 3C.

The optical fiber cores 2 are arranged so as to be the hexagonal closest arrangement when the centers of the cores 21 are connected. The cross canceling member 3C has hexagonal through holes 3Ca. In this way, the optical fiber core wires 2 can be arranged in a hexagonal closest arrangement such as 1+6, 1+6+2×6, 1+6+2×6+3×6, … …, regardless of the number of optical fibers. In this case, the shape of the through hole formed in the cross canceling member may be substantially hexagonal.

Modification 4

Fig. 14 is a cross-sectional view of the optical fiber core wire and the cross-canceling member according to modification 4, corresponding to the line B-B in fig. 1. As shown in fig. 14, the slit 3Db has a width centered on a point obtained by dividing each side of a substantially polygonal shape substantially circumscribed by the plurality of optical fiber cores 2 by the number of optical fiber cores 2 in contact with the side. In the case where the number of optical fiber cores 2 is four as shown in fig. 14, the cross canceling member 3D has four slits 3Db having widths W11, W12, W13, W14 centered at the midpoints of the sides of the substantially quadrangular shape circumscribed with the optical fiber cores 2. The total width of the slits 3Db (w11+w12+w13+w14) is 680 μm, for example. The cutout 3Dc is formed of a part of a circle having a radius of 40 μm, for example, and has a curved shape substantially circumscribing the optical fiber core wire 2. In the example shown in fig. 14, the cutout portion 3Dc is, for example, a circular arc. In a state where the pinching force from the pinching member 4 is not applied to the cross canceling member 3D, the slit 3Db and the cutout 3Dc are formed in a circular arc shape having the same size as the through hole (not shown) and rounded corners, as shown by a thick solid line, and have a substantially square shape with one side of about 250 μm. That is, in fig. 14, the total width (w11+w12+w13+w14) of the slits 3Db is not narrowed but is 680 μm, for example, and therefore, the substantially polygonal shape, that is, the substantially square shape formed by the slits 3Db and the cutout portions 3Dc is a shape in which four corners of a square having one side of 250 μm, which is substantially equal to the length of the two resin coating portions 2b, are curved.

As shown in fig. 1, the cross canceling member 3 is narrowed in width of the slit 3b toward the tip end side by the gripping force applied by the gripping member 4. Fig. 15 is a cross-sectional view of the optical fiber core wire and the cross-over eliminating member in modification 4, corresponding to the C-C line in fig. 1. In fig. 15, the substantially square formed by the slit 3Db and the cutout 3Dc is a quadrangular shape having 160 μm on one side, which is substantially equal in length to the cladding diameter at the rear ends of the two taper portions 2 ab. That is, in FIG. 15, the total width of the slits 3Db (W21+W22+W23+W24) is 320. Mu.m.

As shown in fig. 14 and 15, each of the cut-out portions 3Dc, which are the apex portions of the substantially polygonal shapes circumscribing the plurality of, for example, four optical fiber cores 2, has a curved shape circumscribing the optical fiber cores 2. The sum of the widths (w11+w12+w13+w14) of the slits 3Db located on each side is equal to or greater than the difference between the length of the outer circumference (thick solid line in fig. 14) where the plurality of optical fiber cores 2 are shortest surrounded at the terminal portion of the slit on the rear end side and the length of the outer circumference (thick solid line in fig. 15) where the plurality of optical fiber cores 2 are shortest surrounded at the front end side.

(embodiment 2)

[ optical connector ]

Next, an optical connector using the optical fiber bundle structure 1 will be described. Fig. 16 is a schematic diagram showing the structure of an optical connector of embodiment 2. The optical connector 100 includes an optical fiber bundle structure 1A.

The optical fiber bundle structure 1A includes a ferrule 11 having a hole 11A formed therein, and the hole 11A imparts a gripping force to the inserted cross cancellation member 3. The ferrule 11 has a small hole 11b into which the small diameter portion 2aa of the optical fiber core wire 2 is inserted.

According to embodiment 2 described above, the optical connector 100 can be connected to a multicore fiber or the like incorporated in a connectable connector with low loss.

Fig. 17 is a view showing a state in which the optical fiber core wire of fig. 16 is pushed into the distal end side. As shown in fig. 17, after the optical fiber bundle structure 1A is inserted into the hole 11A of the ferrule 11, the optical fiber core wire 2 may be pushed until the tip of the small diameter portion 2aa reaches the deep portion of the fine hole 11b.

Embodiment 3

[ fiber connection Structure ]

Fig. 18 is a schematic diagram showing the structure of the optical fiber connection structure of embodiment 3. Fig. 19 is a sectional view corresponding to the G-G line of fig. 18. The optical fiber connection structure 200 includes the optical fiber bundle structure 1, the multicore optical fiber 12, and the capillary 13.

The multicore fiber 12 has: a plurality of cores 12a as a plurality of core portions; and a cladding 12b as a cladding portion formed on the outer periphery of the core 12 a. As shown in fig. 19, the multicore fiber 12 has, for example, four cores 12a, and the cores 12a are arranged in a square arrangement. The cores 12a can be connected to the cores 21, respectively.

The optical fiber bundle structure 1 and the multicore optical fiber 12 are connected by bonding or fusion. According to embodiment 3 described above, the cores 12a of the multicore fiber 12 can be connected to the cores 21 of the optical fiber cores 2 with low loss.

Embodiment 4

[ other optical fiber connection Structure ]

Fig. 20 is a schematic diagram showing the structure of the optical fiber connection structure of embodiment 4. Fig. 21 is a sectional view corresponding to the line H-H of fig. 20. The optical fiber connection structure 300 includes the optical fiber bundle structure 1 and the light receiving and emitting element 14.

As shown in fig. 21, the light receiving and emitting element 14 includes, for example, four light receiving and emitting portions 14a as a plurality of light receiving and emitting portions, and the light receiving and emitting portions 14a are arranged in a square arrangement. The light receiving and emitting units 14a are connected to the cores 21, respectively.

By joining the optical fiber bundle structure 1 and the light receiving/emitting element 14, the light receiving/emitting portions 14a of the light receiving/emitting element 14 can be connected to the cores 21 of the optical fiber cores 2 with low loss.

[ method for manufacturing fiber bundle Structure ]

Next, a method of manufacturing the optical fiber bundle structure 1 will be described. Fig. 22 is a flow chart illustrating a method of manufacturing a fiber optic bundle structure.

First, the crossover-eliminating member 3 is inserted into the guide member (step S1: inserting step). Fig. 23 is a schematic view showing the structure of the guide member. Fig. 24 is an I-view of fig. 23. The guide member 5 is an annular member, and has a convex portion 5a having a thickness t protruding in the inner circumferential direction. The thickness t of the convex portion 5a is, for example, 80 μm.

Fig. 25 is a view showing a state in which the cross canceling member is inserted into the guide member. The cross canceling member 3 is inserted into the guide member 5 in such a manner that the protruding portion 5a of the guide member 5 is fitted into the slit 3b of the cross canceling member 3.

Next, the plurality of optical fiber cores 2 are inserted into the cross canceling member 3 (step S2: insertion step). Fig. 26 is a view showing a state in which an optical fiber core is inserted into a cross canceling member. Fig. 27 is a sectional view corresponding to the J-J line of fig. 26. The four optical fiber cores 2 are aligned in a square arrangement, and the four optical fiber cores 2 are inserted from the front end side to the rear end side of the cross canceling member 3. In the cross section shown in fig. 27, the length L1 of one side of the square formed by the slit 3b and the cutout 3c is 250 μm which is approximately equal to the length of the two resin coating portions 2b.

Then, the rear end side of the optical fiber core wire 2 is pulled to the rear end side of the tapered portion 2ab of the glass fiber portion 2a while applying the pinching force F to the cross canceling member 3 so that the rear end of the tapered portion 2ab is positioned inside the cross canceling member 3 (step S3: first pulling step). The pinching force F acting on the cross canceling member 3 may be provided by the guide member 5, or the pinching force F may be provided by hand to the cross canceling member 3.

Fig. 28 is a view showing a state in which the rear end of the tapered portion of the optical fiber core is located inside the guide member. Fig. 29 is a sectional view corresponding to the line K-K of fig. 28. In the state shown in fig. 28 and 29, the inner surface of the crossover-eliminating member 3 is brought into contact with the optical fiber core wire 2 by the pinching force F. In the cross section shown in fig. 29, the length L2 of one side of the square formed by the slit 3b and the cutout 3c is 160 μm which is approximately equal to the length of the two large diameter portions 2ac. In this state, the gap of the slit 3b coincides with the thickness of the convex portion 5a.

Thereafter, the guide member 5 is detached from the cross canceling member 3 (step S4: detachment step).

The optical fiber core wire 2 is pulled toward the rear end side while applying the gripping force F to the cross canceling member 3 so that the small diameter portion 2aa of the glass fiber portion 2a is positioned inside the cross canceling member 3 (step S5: second pulling step). Fig. 30 is a view showing a state where the crossover-eliminating member is inserted into the small diameter portion of the optical fiber core wire. Fig. 31 is a sectional view corresponding to the L-L line of fig. 30. In the state shown in fig. 30 and 31, the inner surface of the crossover-eliminating member 3 is brought into contact with the optical fiber core wire 2 by the pinching force F. In the cross section shown in fig. 31, the length L3 of one side of the square formed by the slit 3b and the cutout 3c is 80 μm which is approximately equal to the length of the two small diameter portions 2 aa.

Here, the thickness t of the protruding portion 5a of the guide member 5 is preferably equal to or greater than the difference between the length (160 μm) of one side of the polygon (quadrangle) that is externally connected to the plurality of optical fiber cores 2 at the rear end of the tapered portion 2ab of the optical fiber core 2 and the length (80 μm) of one side of the polygon (quadrangle) that is externally connected to the plurality of optical fiber cores 2 at the front end of the tapered portion 2ab of the optical fiber core 2. When this condition is satisfied, when the guide member 5 is detached from the crossover-eliminating member 3, a gap corresponding to the thickness t of the protruding portion 5a is generated in the slit 3b. As a result, the width of the slit 3b is narrowed from the rear end of the tapered portion 2ab toward the front end in accordance with the diameter reduction of the optical fiber core wire 2, and the cross canceling member 3 abuts the optical fiber core wire 2 over the entire area in the longitudinal direction of the tapered portion 2ab of the optical fiber core wire 2, thereby preventing the optical fiber core wire 2 from crossing.

Then, the cross cancellation member 3 is inserted into the hole of the ferrule while applying the pinching force F to the cross cancellation member 3 (step S6: ferrule insertion step). Specifically, for example, the cross canceling member 3 is inserted into the hole 11a of the ferrule 11 shown in fig. 16.

Industrial applicability

The present invention is suitably applied to an optical fiber bundle structure in which cores of single-core optical fibers are arranged at positions corresponding to cores of multi-core optical fibers.

Reference numerals illustrate:

1. 1A optical fiber bundle structure

2. Optical fiber core wire

2a glass fiber portion

2aa diameter-reducing portion

2ab taper

2ac thick diameter portion

2b resin coating part

3. 3A, 3B, 3C, 3D cross-over cancellation member

3a, 3Aa, 3Ba, 3Ca through holes

3b, 3Bb, 3Db slit

3c, 3Bc, 3Dc cut-out portions

4. Gripping member

5. Guide member

5a convex part

11. Core insert

11a hole part

11b pore portion

12. Multi-core optical fiber

13. Capillary tube

14. Light receiving and emitting element

14a light receiving and emitting part

21. 12a core

22. 12b cladding

23. Coating part

100. Optical connector

200. 300 fiber optic connection.

Claims

1. An optical fiber bundle structure, which is characterized in that,

the optical fiber bundle structure is provided with:

a plurality of optical fiber cores;

a cross elimination member through which the plurality of optical fiber cores extend in a longitudinal direction; and

a grip member that imparts a grip force to the crossover-elimination member,

the plurality of optical fiber cores sequentially comprise a glass fiber part and a resin coating part for coating the glass fiber with resin from the front end,

the glass fiber part comprises a small diameter part, a cone-shaped part and a large diameter part in sequence from the front end,

the cross cancellation member has: a through hole formed at a rear end side of the cross cancellation member and through which the resin coating portion of the optical fiber core wire passes; a slit extending from a front end of the crossover-elimination member to a middle of a rear end side; and a notch portion formed in a region where the through hole is projected to the distal end side of the cross canceling member and configured to abut against the optical fiber core wire,

the slit has a width in a cross section of the cross canceling member orthogonal to the longitudinal direction, the cross canceling member extending from a front end to a rear end of the cross canceling member, the cross canceling member having a width at a point obtained by dividing each side of a polygon which circumscribes the plurality of optical fiber cores by the number of optical fiber cores which are in contact with the side,

the width of the slit on each side is equal to or greater than the difference between the length of one side of the polygon that is circumscribed by the plurality of optical fiber cores at the terminal end of the slit on the rear end side and the length of one side of the polygon that is circumscribed by the plurality of optical fiber cores at the front end side.

2. An optical fiber bundle structure, which is characterized in that,

the optical fiber bundle structure is provided with:

a plurality of optical fiber cores;

a grip member that imparts a grip force to the crossover-elimination member,

the slit has a width in a cross section of the cross canceling member orthogonal to the longitudinal direction, the cross canceling member extending from a front end to a rear end of the cross canceling member, the cross canceling member having a width at a point in a middle of the cross section, the point being obtained by dividing each side of a substantially polygonal shape circumscribing the plurality of optical fiber cores by the number of optical fiber cores in contact with the side,

each vertex of a substantially polygonal shape, in which the slit circumscribes the plurality of optical fiber cores, has a curved shape, and the sum of the widths of the slits located on the respective sides is equal to or greater than a difference between a length of an outer circumference of a terminal portion of the slit on a rear end side, the outer circumference of the slit, the outer circumference of the terminal portion of the slit surrounding the plurality of optical fiber cores in a shortest manner, and a length of an outer circumference of the terminal portion of the slit, the terminal portion of the slit surrounding the plurality of optical fiber cores in a shortest manner.

3. The optical fiber bundle structure according to claim 1 or 2, wherein,

the grip member is a ring fitted to the distal end side of the crossover-eliminating member.

4. The optical fiber bundle structure according to claim 1 or 2, wherein,

the plurality of optical fiber cores are arranged in a square shape at the small diameter portion.

5. The fiber optic bundle structure according to claim 4, wherein,

the number of the optical fiber core wires is four or nine.

6. The optical fiber bundle structure according to claim 1 or 2, wherein,

the plurality of optical fiber cores are arranged most closely in a hexagonal shape at the small diameter portion.

7. The fiber optic bundle structure of claim 6, wherein,

the number of the optical fiber cores is seven or nineteen.

8. An optical connector, characterized in that,

the optical connector is provided with the optical fiber bundle structure according to any one of claims 1 to 7,

the grip member is a ferrule formed with a hole portion that imparts a grip force to the inserted crossover-elimination member.

9. An optical fiber connection structure, which is characterized in that,

the optical fiber connection structure is provided with:

the optical fiber bundle structure of any one of claims 1-7; and

and a multi-core optical fiber having a plurality of core portions connected to the cores of the plurality of optical fiber cores and a cladding portion formed on the outer periphery of the core portions.

10. An optical fiber connection structure, which is characterized in that,

the optical fiber connection structure is provided with:

the optical fiber bundle structure of any one of claims 1-7; and

and a plurality of light receiving/emitting units connected to the cores of the plurality of optical fiber cores.

11. A method for manufacturing an optical fiber bundle structure is characterized in that,

the manufacturing method of the optical fiber bundle structure comprises the following steps:

an insertion step of inserting a crossover-eliminating member into a circular ring-shaped guide member so that a protrusion protruding in an inner circumferential direction of the guide member is fitted into a slit, the crossover-eliminating member being configured to allow a plurality of optical fiber cores to pass through in a longitudinal direction, the plurality of optical fiber cores having a glass fiber portion and a resin coating portion coating a resin on the glass fiber in this order from a front end, the slit having a width in a cross section orthogonal to the longitudinal direction of the crossover-eliminating member centered on a point extending from a front end to a rear end side of the crossover-eliminating member, the point being obtained by dividing each side of a polygon circumscribed by the plurality of optical fiber cores by a number of optical fiber cores in contact with the side, the width of the slit on each side being equal to or greater than a difference between a length of one side of a polygon circumscribed by the plurality of optical fiber cores at a terminal end of the slit on a rear end side and a length of one side of the polygon circumscribed by the plurality of optical fiber cores on a front end side;

a penetration step of penetrating the plurality of optical fiber cores from the front end side to the rear end side of the cross canceling member while the plurality of optical fiber cores are aligned in a predetermined arrangement;

a pulling step of pulling the optical fiber core wire toward a rear end side while applying a gripping force to the cross canceling member until a small diameter portion of the glass fiber portion is positioned inside the cross canceling member, the glass fiber portion having the small diameter portion, the tapered portion, and the large diameter portion in this order from a front end;

a detaching step of detaching the guide member from the crossover-eliminating member; and

a ferrule insertion step of inserting the crossover-eliminating member into the hole of the ferrule while applying a gripping force to the crossover-eliminating member,

the cross cancellation member has: a through hole formed at a rear end side of the cross cancellation member and through which the resin coating portion of the optical fiber core wire passes; a slit extending from a front end of the crossover-elimination member to a middle of a rear end side; and a cutout portion formed in a region where the through hole is projected to the distal end side of the cross cancellation member, and configured to abut against the optical fiber core wire.

12. The method of manufacturing a fiber optic bundle structure according to claim 11,

the traction process includes:

a first pulling step of pulling the optical fiber core wire toward a rear end side until a rear end of the tapered portion of the glass fiber portion is positioned inside the crossover-eliminating member; and

a second pulling step of pulling the optical fiber core wire toward a rear end side until the small diameter portion of the glass fiber portion is positioned inside the crossover-eliminating member,

the disassembly process is performed between the first pulling process and the second pulling process.

13. The method of manufacturing a fiber optic bundle structure according to claim 11 or 12, wherein,

the thickness of the protruding portion of the guide member is equal to or greater than the difference between the length of one side of the polygon that circumscribes the plurality of optical fiber cores at the rear end of the tapered portion of the optical fiber core and the length of one side of the polygon that circumscribes the plurality of optical fiber cores at the front end of the tapered portion of the optical fiber core.